Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH V2 0/4] PCI: ACPI: Setting up DMA coherency for PCI device from _CCA attribute | Date | Tue, 25 Aug 2015 20:48:24 +0200 |
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On Wednesday 26 August 2015 00:33:25 Suravee Suthikulpanit wrote: > This patch adds support to setup DMA coherency for PCI device using > the ACPI _CCA attribute. According to the ACPI spec, the _CCA attribute > is required for ARM64. Therefore, this patch is a pre-req for ACPI PCI > support for ARM64 which is currently in development. > > Also, this should not affect other architectures that does not define > CONFIG_ACPI_CCA_REQUIRED, since the default value is coherent. >
We only support ACPI on SBSA compliant platforms, and SBSA mandates cache-coherent PCI, so I don't think this is actually needed, just use coherent all the time and do WARN_ON(!CCA) to catch people that try to incorrectly use ACPI on a non-SBSA platform.
Arnd
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